Bit retainer

Abstract

An improved bit retainer having a retainer body that includes an arcuate top portion defining a radially expandable area. The bit retainer including a pair of opposed arcuate legs depending from the arcuate top portion, the pair of opposed arcuate legs having a radial cross-section greater than the radial cross-section of the radially expandable area. Each leg includes a cavity adjacent a distal end of the leg. The bit retainer adapted to engage an annular groove of a shank of a pick or unitary bit/holder when the bit is inserted into a bore of a base block and retain the bit within the bore of the base block. A first embodiment of the bit retainer having a flat side profile and a second embodiment of the bit retainer having a curved side profile.

What is claimed is: 
     
       1. A retainer for a bit assembly, comprising:
 a retainer body including a first surface equally spaced from a second surface, a radially expandable and deformable arcuate top portion, and a first non-deformable arcuate leg extending to a first flat distal surface of the first non-deformable arcuate leg parallel and opposite a second flat distal surface of a second non-deformable arcuate leg, each non-deformable arcuate leg depending from opposite sides of the expandable and deformable arcuate top portion, the first flat distal surface and the second flat distal surface extending from the first surface to the second surface of the retainer body, and the radially expandable arcuate top portion comprising a periphery of 180 degrees and a constant radial cross-section over the 180 degree periphery; 
 the first non-deformable arcuate leg including a first cavity and the second non-deformable arcuate leg including a second cavity, the first cavity inwardly extending from the first flat distal surface of the first non-deformable arcuate leg opposite the second flat distal surface of the second non-deformable arcuate leg and the second cavity inwardly extending from the second flat distal surface of the second non-deformable arcuate leg opposite the first flat distal surface of the first non-deformable arcuate leg; and 
 a radial cross-section of the first non-deformable arcuate leg and the second non-deformable arcuate leg being greater than the constant radial cross-section of the radially expandable and deformable arcuate top portion to reduce a risk of failure at the radial cross-section of the first non-deformable arcuate leg and the second non-deformable arcuate leg. 
 
     
     
       2. The retainer of  claim 1 , wherein the retainer body has one of a flat profile and a curved profile. 
     
     
       3. The retainer of  claim 1 , wherein the first cavity and the second cavity are U-shaped. 
     
     
       4. The retainer of  claim 1 , wherein the first cavity comprises a first open end opposite the second cavity and the second cavity comprises a second open end opposite the first cavity. 
     
     
       5. A bit assembly, comprising:
 a base block comprising a bore; 
 a bit comprising:
 a forward body portion; and 
 a generally cylindrical shank depending axially from the forward body portion, the shank comprising an annular groove adjacent a distal end of the shank, wherein the shank is adapted to provide a small clearance between the bore of the base block; and 
 
 a retainer comprising:
 a retainer body including a first surface equally spaced from a second surface, a radially expandable and deformable arcuate top portion, and a first non-deformable arcuate leg extending to a first flat distal surface of the first non-deformable arcuate leg parallel and opposite a second flat distal surface of a second non-deformable arcuate leg, each non-deformable arcuate leg depending from opposite sides of the expandable and deformable arcuate top portion, the first flat distal surface and the second flat distal surface extending from the first surface to the second surface of the retainer body, and the radially expandable and deformable arcuate top portion comprising a periphery of 180 degrees and a constant radial cross-section over the 180 degree periphery; 
 the first non-deformable arcuate leg including a first cavity and the second non-deformable arcuate leg including a second cavity, the first cavity inwardly extending from the first flat distal surface of the first non-deformable arcuate leg opposite the second flat distal surface of the second non-deformable arcuate leg and the second cavity inwardly extending from the second flat distal surface of the second non-deformable arcuate leg opposite the first flat distal surface of the first non-deformable arcuate leg, the first non-deformable arcuate leg and the second non-deformable arcuate leg adapted to engage the annular groove of the shank; and 
 a radial cross-section of the first non-deformable arcuate leg and the second non-deformable arcuate leg being greater than the constant radial cross-section of the radially expandable and deformable arcuate top portion to reduce a risk of failure at the radial cross-section of the first non-deformable arcuate leg and the second non-deformable arcuate leg. 
 
 
     
     
       6. The bit assembly of  claim 5 , wherein the retainer body has one of a flat profile and a curved profile. 
     
     
       7. The bit assembly of  claim 5 , wherein the first cavity and the second cavity are U-shaped. 
     
     
       8. The bit assembly of  claim 5 , wherein the shank is solid. 
     
     
       9. The bit assembly of  claim 5 , wherein the first cavity comprises a first open end opposite the second cavity and the second cavity comprises a second open end opposite the first cavity. 
     
     
       10. A combination comprising:
 a bit comprising:
 a forward body portion; and 
 a generally cylindrical shank depending axially from the forward body portion, the shank comprising an annular groove adjacent a distal end of the shank; and 
 
 a retainer comprising:
 a retainer body including a first surface equally spaced from a second surface, a radially expandable and deformable arcuate top portion, and a first non-deformable arcuate leg extending to a first flat distal surface of the first arcuate leg parallel and opposite a second flat distal surface of a second non-deformable arcuate leg, each non-deformable arcuate leg depending from opposite sides of the expandable and deformable arcuate top portion, the first flat distal surface and the second flat distal surface extending from the first surface to the second surface of the retainer body, and the radially expandable and deformable arcuate top portion comprising a periphery of 180 degrees and a constant radial cross-section over the 180 degree periphery; 
 the first non-deformable arcuate leg including a first cavity and the second non-deformable arcuate leg including a second cavity, the first cavity inwardly extending from the first flat distal surface of the first non-deformable arcuate leg opposite the second flat distal surface of the second non-deformable arcuate leg and the second cavity inwardly extending from the second flat distal surface of the second non-deformable arcuate leg opposite the first flat distal surface of the first non-deformable arcuate leg, the first non-deformable arcuate leg and the second non-deformable arcuate leg adapted to engage the annular groove of the shank; and 
 a radial cross-section of the first non-deformable arcuate leg and the second non-deformable arcuate leg being greater than the constant radial cross-section of the radially expandable and deformable arcuate top portion to reduce a risk of failure at the radial cross-section of the first non-deformable arcuate leg and the second non-deformable arcuate leg. 
 
 
     
     
       11. The combination of  claim 10 , wherein the retainer body has one of a flat profile and a curved profile. 
     
     
       12. The combination of  claim 10 , wherein the first cavity and the second cavity are U-shaped. 
     
     
       13. The combination of  claim 10 , wherein the shank is solid. 
     
     
       14. The combination of  claim 10 , wherein the first cavity comprises a first open end opposite the second cavity and the second cavity comprises a second open end opposite the first cavity.